Sparrow Mail for iOS

I've always been happy with Apple's Mail.app for OS X, so I wasn't all that interested in Sparrow for Mac. But for $3, Sparrow for iOS is a no-brainer. The built-in iOS Mail app is OK, but I think it could be improved in a few small but important ways. Sparrow seems to get most of the improvements out of the box, and they'll hopefully be more agile than Apple in addressing feature requests as they mature.

It's too soon to say that one is hands-down better than the other: Apple is constrained by a need to meet the top needs of 100+ million iOS users, whereas Sparrow has the counter-intuitive advantage of a very small install base made up primarily of nerds. Apple needs to constantly choose what (if anything) to add to their elegantly simple mail program so that everyone from Tech Writers to Grandfathers can use it easily. Sparrow is trying to fill a small but growing niche, and really only needs to make themselves (and a million or so people like them, eventually) happy with the product.

Things I love about Sparrow:

Different signature for each account(!!!). Why has Apple not gotten to this yet?

Reply to a message, then - without leaving the reply panel - decide to Reply All with one tap. If you're really indecisive, you can easily toggle back to Reply

Push, of course. This ball is in Apple's court, not Sparrow's, and hopefully Apple will make a way to grant approval soon.

TextExpander integration. With this, I would probably ditch the built-in Mail app for good.

Ability to "de-thread" messages so that they fill the Inbox chronologically, not grouped by conversation

Corollary to above: ability to flip from one message to next without navigating back to the inbox. (Or am I missing this in the current version?) Reeder has spoiled me on this, and again - I don't know why Apple hasn't done it yet. I can't tell you how often I've come into Mail after 10-15 minutes in Reeder, and found myself trying to flip from the end of one message to the beginning of the next. I typically try two or three times before I remember that it's not possible. (See: Insanity, Einstein's definition of.)

I may update this post as I think of other items for the above categories, so stay tuned!